Effects of the degree of polymerization of oligosaccharides on the properties of ground mixtures.

Abstract

X-Ray analysis, differential thermal analysis (DTA) and infrared (IR) spectroscopy have been used to investigate the influence of the degree of polymerization of oligosaccharides on the dispersion state and the interaction of drugs (aspirin and methylparaben) during grinding with oligosaccharides. When a drug was ground with maltoheptaose or maltopentaose, the crystalline peaks of the drug in the powder X-ray diffraction pattern and the heat of fusion of the drug on DTA disappeared, and some IR spectral changes were observed. In the case of the ground mixture with maltotriose, an amorphous state of the drug was observed from the powder X-ray diffraction and DTA results, but there was no change in the IR spectrum. In the case of the ground mixture with maltose, the crystallinity of the drug was scarcely altered by the grinding.These results indicate that in the ground mixtures with maltopentaose and maltoheptaose, drug molecules were dispersed monomolecularly in the hydrogen-bonded networks of oligosaccharides. On the other hand, in the maltotriose system, although the drug was in an amorphous state, the drug was not in a molecular dispersion due to the low degree of polymerization of maltotriose.